diff --git a/cmd/oras/root/manifest/index/update.go b/cmd/oras/root/manifest/index/update.go
index 64bdf0978..b48deb0ff 100644
--- a/cmd/oras/root/manifest/index/update.go
+++ b/cmd/oras/root/manifest/index/update.go
@@ -22,9 +22,11 @@ import (
 	"strings"
 
 	"github.com/opencontainers/go-digest"
+	"github.com/opencontainers/image-spec/specs-go"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/spf13/cobra"
 	"oras.land/oras-go/v2"
+	"oras.land/oras-go/v2/content"
 	"oras.land/oras/cmd/oras/internal/argument"
 	"oras.land/oras/cmd/oras/internal/command"
 	oerrors "oras.land/oras/cmd/oras/internal/errors"
@@ -108,12 +110,26 @@ func updateIndex(cmd *cobra.Command, opts updateOptions) error {
 	if err != nil {
 		return err
 	}
-	desc, content, err := packIndex(&index, manifests)
-	if err != nil {
-		return err
+	// desc, content, err := packIndex(&index, manifests)
+	// if err != nil {
+	// 	return err
+	// }
+
+	updatedIndex := ocispec.Index{
+		Versioned: specs.Versioned{
+			SchemaVersion: 2,
+		},
+		MediaType:    index.MediaType,
+		ArtifactType: index.ArtifactType,
+		Manifests:    manifests,
+		Subject:      index.Subject,
+		Annotations:  index.Annotations,
 	}
+	indexBytes, _ := json.Marshal(updatedIndex)
+	desc := content.NewDescriptorFromBytes(updatedIndex.MediaType, indexBytes)
+
 	opts.Println("Updated the index")
-	return pushIndex(ctx, target, desc, content, opts.Reference, opts.extraRefs, opts.AnnotatedReference(), opts.Printer)
+	return pushIndex(ctx, target, desc, indexBytes, opts.Reference, opts.extraRefs, opts.AnnotatedReference(), opts.Printer)
 }
 
 func fetchIndex(ctx context.Context, target oras.ReadOnlyTarget, opts updateOptions) (ocispec.Index, error) {